I was in the Petalburg Gym, out of healing items and down to my last pokemon, Numel. By sheer dumb luck, every single one of my pokemon at the time was male, and there's an Ace Trainer in there who has a Delcatty that knows Attract. She almost always used that move whenever I sent out a new pokemon, and she had haxed my entire team to death: "Swampert is immobilized by love!" "Mightyena is immobilized by love!" "Manectric is immobilized by love!" every single turn until she had KOed everything else with Doubleslap without even getting hit once.
So then I send out my last pokemon, a crappy underleveled Numel that I didn't even really want to catch, but it got in my way in Fiery Path and I had an extra pokeball so whatever. And she uses Doubleslap on the first turn and gets all five hits and I'm down to 2 HP, and I only did about 10% damage back to it with Ember. So I was thinking, ugh, I'm going to lose this battle and have to go all the way back to the pokemon center, this is such a waste of time, Delcatty is bullshit, etc. But then I was saved, by a stroke of luck so unlikely that only the pokemon AI we know and love would ever think of it.
She used Attract on my Numel.
Numel had the ability Oblivious.
I hit Delcatty with Ember again.
She spent the entire rest of the battle doing nothing but spamming Attract, for 8 more turns. I ended up winning the battle and smirking to myself all the way through the rest of the gym.